Thanks for the question. I assume you are doing this project? http://www.sciencebuddies.org/science-f ... background
. If not, what project are you doing? What is your "scientific question"? Have you come up with a hypothesis, yet?
If you have not done so already, the answer can be found on that project page in the "background information" section (see link above). There you can find their ideal living temperature. You can then use that information to look up how deep in the ocean they can be found, based on the temperature and depth of water.
A great way to get information is to first identify an article that addresses the topic you are interested in. Look at the bottom of the webpage (or at the end of the book) at the "References" or "Literature Cited" section to find similar information. Researchers who perform experiments (just like you are doing) always do research first, to find out about organisms, in your case, P. lunula
Here is some information on bioluminescence:http://www.annualreviews.org/eprint/pbW ... 308-081028
A website all about Bioluminescence!http://www.lifesci.ucsb.edu/~biolum/http://www.lifesci.ucsb.edu/~biolum/org ... ohome.html
Also, one last tip for researching online: Google has a search engine, "Google Scholar": http://scholar.google.com/
. You can find articles from scientists and researchers here. The information you get from those articles will be more accurate than those from wikipedia. Let me know if you have trouble using this site, there is a TON of information, some of which may be really confusing.
Once you get to a website, here are some tips to use so you know if it is a resource with good scientific information:
1. Use the "search" function...(Control + f) to look up key words such as bioluminescence, P. lunula
, dinoflagellates, etc.
2. Does this article or book address your topic? Have your scientific question in mind when looking for answers
3. Is this a legitimate website? Was it written by a University, Research team, biologists, Scientific papers/journals?
Hope this helps you get started. Let me know how it goes and if you need more help.